Some conventional cap closures for sealing bottles include a liner over the mouth of the bottle, and a cap with a central opening which covers the liner and engages the neck finish of the bottle. Known specific examples are discussed below.
Boege et al., in U.S. Pat. No. 4,773,552, disclose a closure for sample bottles in which a plurality of disks fit into a metal cap having a center hole. The disks are retained in the cap by prongs around the periphery of the disks which are frictionally fit to the inside skirt of the cap. One of the disks is a liner which does not protrude into the hole in the cap.
Other typical cap closures include a liner/stopper combination which fits into a hole in the cap, and is frictionally retained there. The stopper completely fills the hole in the cap such that the top of the stopper and the top of the cap form the outer surface of the cap. In time, these liners tend to be released from the surrounding cap, particularly when the surrounding cap is a non-resilient material, such as poly-propylene.
Brennan et al., in U.S. Pat. No. 3,709,395, disclose a container closure including a liner--top of the cap--liner sandwich, wherein the liners are attached by a stopper through a hole in the cap.